Computer chassis house processors, memory devices, power supplies, expansion cards and several other components. A computer chassis should protect the computer components from dust, static electricity, external electromagnetic interference (EMI) emissions, physical impact and other external factors. Computer chassis also protect users and the environment from EMI emissions generated by the computer components. In a typical application, a computer chassis has a high structural integrity to protect against physical impact, and conductive, shielding materials to reduce EMI emissions. The conductive components of the computer are also grounded to the chassis to protect users and computer components from electric shock.
In the competitive computer industry, it is important to efficiently install the components in the chassis to control the cost to assemble a computer or upgrade computer components. The efficiency of installing computer components in the chassis is a function of the ease of attaching, removing, or replacing components in the chassis. Additionally, motherboards and other components should be easily accessible for upgrading and expanding the hardware of computers. Thus, the design of the computer chassis for efficient assembly and upgrading directly impacts the overall cost of manufacturing a computer.
FIG. 1 is a schematic isometric overview of a computer system 10 including a computer 12, a monitor 14 coupled to the computer 12, and a keyboard 16 coupled to the computer 12. The operative components of the computer 12 are housed in a chassis 20. FIG. 2 is a schematic isometric top view illustrating the installation of an NLX motherboard 22 into the chassis 20. The NLX motherboard 22 is installed by sliding the motherboard 22 along guides 23 (arrow A). The motherboard 22 includes a metal gasket 24 with a row of beryllium copper spring fingers 26. As the motherboard 22 slides into the chassis 20, the spring fingers 26 slide across an interior chassis wall 28 to maintain a ground contact between the motherboard 22 and the chassis 20. After the motherboard 22 is installed in the chassis 20, the gasket 24 obstructs an opening 29 in the chassis wall 28 and shields the motherboard 22 from EMI emissions external environmental factors.
One drawback of the chassis 20 is that it may not adequately shield the computer components from EMI emissions. To adequately shield the computer components, an EMI shield must electrically contact the chassis at enclosure seam gaps. The prior art gasket 24 may not provide adequate EMI shielding because the spring fingers 26 may bend or break as they slide across the chassis wall 28 during installation or removal of the motherboard 22. As a result, the spring fingers 26 may not contact the chassis 20 in a manner that properly grounds the motherboard 22 and restricts EMI emissions.
Another drawback of the chassis 20 is that it may not have sufficient structural integrity to protect the computer components during shipping and operation. To permit installation of the motherboard 22, a backplate 30 is removed from the chassis 20 and the rear corner of the sidewall 28 includes a notch 27 to receive the motherboard 22. The removable backplate 30 detrimentally effects the structural integrity and strength of the chassis 20 because the entire rear surface of the chassis 20 is a separate component that may become loose. Additionally, the notch 27 reduces the strength of the sidewall 28 such that the sidewall 28 is subject to twisting at the rear corner of the chassis 20. The chassis 20, therefore, may not have sufficient structural integrity to adequately protect the computer components.
The chassis 20 also presents a manufacturing concern because it may impair efficient installation and/or removal of the motherboard 22. For example, because the fingers 26 may be damaged or destroyed as they slide across the interior wall 28, installers must use great care and slowly slide the motherboard 22 into the chassis 20. Installing and removing NLX motherboards 22 is accordingly a time consuming part of assembling or upgrading computers. Moreover, if the fingers 26 are damaged, more time is required to repair the fingers 26 or replace the gasket 24. Thus, the chassis 20 may significantly impair the manufacturing and repair costs of computers with NLX motherboards.